This precision speed control was obtained in an Electronic Design from the 90's. The output final stage power transistors must be in accordance with the motor power.
This circuit is from the Motorola Linear Databook of 1990. The circuit controls a Triac from a...
The circuit shown uses the LM324, but can be implemented with other operational ones. The source...
This circuit makes use of a stroboscopic tube, a component that no longer exists today. The...